Fluid sample stream conditioning

ABSTRACT

The instant disclosure relates to apparatus for and a method of conditioning a fluid sample stream, for example, for passage through an analytical instrument. The method involves passing a gas under pressure into a vortex tube so that the gas separates into two exit streams from the vortex tube, a heated stream and a cooled stream. The cooled stream is passed into heat exchange relationship with the fluid sample stream so that the fluid sample is cooled. The heated stream is passed into heat exchange relationship with the cooled fluid sample so that the fluid sample is heated, whereby the fluid sample stream is conditioned. The apparatus includes a fluid conduit having an inlet and an outlet. A hollow heat exchange jacket having a cooling section and a heating section surrounds the conduit so as to form a heating section and a cooling section in the conduit. Means are provided for introducing a gas under pressure into a vortex tube so that the gas separates into two exit streams from the vortex tube, a heated stream and a cooled stream. Means are provided for passing the heated gas stream into the heating section of the heat exchange jacket and means are also provided for passing the cooled gas stream into the cooling section of the heat exchange jacket. Suitable means are provided for passing the fluid sample stream through the conduit so that it travels through the section surrounded by the cooling section of the jacket and through the section surrounded by the heating section, whereby the fluid sample stream is cooled and heated.

iii ties iei [72] Inventor J0eA.lP0rter Whittier, (Ialii. [21] Appl. No.6,058 [22] 'Filed Jan. 27, 11970 [45] Patented [73] Assignee Dec. 21,19711 Becitman Instruments, inc.

1541 IFLUHD SAMPLE STREAM CONDITIONING 117 Claims, 1 Drawing Iiig.

Primary Examiner-William .l. Wye Att0rneys-William F. McDonald andRobert]. Steinmeyer ABSTRACT: The instant disclosure relates toapparatus for and a method of conditioning a fluid sample stream, forexample, for passage through an analytical instrument. The methodinvolves passing a gas under pressure into a vortex tube so that the gasseparates into two exit streams from the vortex tube, a heated streamand a cooled stream. The cooled stream is passed into heat exchangerelationship with the fluid sample stream so that the fluid sample iscooled. The heated stream is passed into heat exchange relationship withthe cooled fluid sample so that the fluid sample is heated, whereby thefluid sample stream is conditioned. The apparatus includes a fluidconduit having an inlet and an outlet. A hollow heat exchange jackethaving a cooling section and a heating section surrounds the conduit soas to form a heating section and a cooling section in the conduit. Meansare provided for introducing a gas under pressure into a vortex tube sothat the gas separates into two exit streams from the vortex tube, aheated stream and a cooled stream. Means are provided for passing theheated gas stream into the heating section of the heat exchange jacketand means are also provided for passing the cooled gas stream into thecooling section of the heat exchange jacket. Suitable 'means areprovided for passing the fluid sample stream through the conduit so thatit travels through the section surrounded by the cooling section of thejacket and through the section surrounded by the heating section,whereby the fluid sample stream is cooled and heated.

rwm SAMPLE STREAM commonmc BACKGROUND OF THE INVENTION This inventionrelates to conditioning a fluid sample stream. it is particularlyapplicable to conditioning a gas stream for analysis. For example, if agas stream is to be analyzed for its oxygen content, it will be passedthrough an oxygen sensing instrument. If the gas stream contains watervapor at a concentration such that some water vapor can separate out inthe analytical apparatus, the separated water vapor can interfere withthe analysis and cause a false reading by the instrument. Accordingly,it is usually desired to condition the fluid sample stream, in this casea water vapor containing gas, by lowering the water vapor content in thegas stream to such a level that any water vapor remaining in the gasstream after the conditioning operation will not condense out in theanalytical instrument. In other cases it may be desired to first heatthe fluid sample stream and then cool it.

Apparatus for conditioning a fluid sample stream has been known in thepast. Past apparatus and processes for conditioning the fluid samplehave normally involve cooling the sample stream so as to condense outwater vapor and then heating the stream to bring it above the saturationpoint again so that any remaining water vapor will not condense out inthe analytical instrument. Relatively cumbersome apparatus has been usedto accomplish this purpose, however. A complicated cooling system andassociated pumps and piping have been used for the cooling step andsimilarly a complicated heat generator, heat exchanger and related pumpsand piping have been required for the heating step. Yet another set ofpiping and pumps have been required to pull or push the fluid samplestream through the heat exchanger and on into and through the analyticalinstrument.

In general, the more complicated a process is or the more complicatedapparatus is, the more difficult and expensive it is to operate andmaintain. Thus, there has been a need in this field to improve thereliability of the sample analysis and conditioning process by providinga simpler, more reliable process and apparatus for conditioning thefluid sample stream.

SUMMARY OF THE INVENTION It is an object of the instant invention toprovide apparatus for and a method of conditioning a fluid sample streamwhich is simpler and more reliable than prior art processes andapparatus.

Advantageously, the instant invention requires only a source ofcompressed air to provide the working fluid for the system and tosatisfy all the pumping requirements of the system. Thus, desirably,outside of the source of compressed gas, only a single pump (operated bythe compressed gas) is needed for the entire system. It is a furtheradvantage of the process and apparatus of the instant invention that theconditioning of the fluid sample stream is easily controlled andregulated. The apparatus desirably is quite simple and has few movingparts, so that maintenance is reduced to a minimum.

The instant invention relates to apparatus for conditioning a fluidsample stream. The apparatus includes a fluid conduit having an inletand an outlet. A hollow heat exchange jacket, having a cooling sectionand a heating section, surrounds the conduit so as to form a heatingsection and a cooling section in the conduit. Means are provided forintroducing a gas under pressure into a vortex tube so that the gasseparates into two exit streams from the vortex tube, a heated streamand a cooled stream. Means are also provided for passing the heated gasstream into the heating section of the heat exchange jacket and forpassing the cooled gas stream into the cooling section of the heatexchange jacket. Means are provided for passing the fluid sample streamthrough the conduit so that it travels through the section surrounded bythe cooling section of the jacket and through the section surrounded bythe heating section whereby the fluid sample stream is cooled andheated, either cooled first and then heated, or heated first and thencooled.

The process according to the instant invention relates to conditioning afluid sample stream wherein a gas under pressure is passed into a vortextube so that the gas separates into two exit streams from the vortextube, a heated stream and a cooled stream. The cooled stream is passedinto heat exchange relationship with the fluid sample stream so that thefluid sample is cooled. The heated stream is passed into heat exchangerelationship with the fluid sample stream so that the fluid sample isheated, whereby the fluid sample stream is conditioned.

Other objects and advantages of the instant invention will be apparentfrom the following description in conjunction with the accompanyingdrawing.

BRIEF DESCRIPTION OF THE DRAWING The single figure of the drawing showsan apparatus according to the instant invention which is also suitablefor practicing the process according to the instant invention.

DETAILED DESCRIPTION Referring now to the drawing, the apparatusaccording to the instant invention may be seen to include a fluidconduit, shown as a vertically disposed tube 10. Tube 10 has an inlet 12and an outlet 14. A hollow heat exchange jacket 16, having a coolingsection 18 and a heating section 20, surrounds conduit tube It so as toform a heating section 22 and a cooling section 24 in the conduit.Means, such as supply line 26, are provided for introducing a gas underpressure into a vortex tube 28. Vortex tubes are also called Ranquetubes or Hilsch tubes or hot/cold pipes. These devices are now wellknown in the art. A description of the construction and some of theoperating features of such a tube may be found in U.S. Pat. No. 1,952,28l which issued Mar. 27, 1934, to Ranque. In general, a vortex tubeincludes a chamber having the shape of a surface of revolution such as acylinder. The chamber has an inlet pipe for tangentially introducing thegas to be treated into a central region of the chamber. A gyratorymotion is imparted to the gas as it enters the chamber, and means, suchas a restricted orifice between one end of the cylinder and thetangential inlet, divide the gas into two concentric sheets moving alongeach other so that the outer sheet is compressed by the inner sheet. Thework thus produced causes a substantial rise in temperature in the outersheet and a corresponding drop in the temperature of the inner sheet.

Thus, in the vortex tube 28 of the instant invention, the gas separatesinto two exit streams from the vortex tube, a heated stream and a cooledstream. Means such as pipe 30 are provided for passing the heated gasstream into the heating section 20 of jacket 16. Similarly, means suchas pipe 32 are provided for passing the cooled gas stream into thecooling section 118 of jacket 116.

The two sections 18, 20 of the heat exchange jacket are separated fromone another by separator 34. Each has its own discharge vent 36. Asshown, the conduit tube 10 is generally vertically disposed and when thefluid sample is to be first cooled and then heated, the cooling section24 of the conduit is below the heating section 22 of the conduit. Thetemperature differential between the heating sections 20, 22 and thecooling sections 18, 24 is controlled by means of a valve 38 located inpipe 30 which regulates the passage of the heated gas stream from thevortex tub 28 into the heating section 20 of jacket 16.

A vertically disposed T or Y-shaped junction tube 40 is connected at itsupper arm 42 to the inlet 12 of the conduit and at its base 44 to asource of sample gas. When the fluid sample stream being conditioned isa water vapor containing gas stream, the water vapor will condense andseparate from the sample stream in the cooling section 24. The watervapor will run down through tube 40 into vessel 46 which is sealed tothe lower arm 48 of junction tube 40. Thus it can readily be seen thatsome of the sample gas and the condensed water pass downwardly into thevessel 46 and the remainder of the sample gas will pass upwardly throughthe conduit tube where it is conditioned. 1

' A container 50 for an analytical instrument, for example, an oxygenanalyzer, is mounted on the outlet 14 of conduit tube 10 so that theconditioned sample gas passes therethrough. A sample stream dischargeline 52 passes downwardly from instrument container 50 into and issealed in the condensed water vessel 46. Outlet pipe 54 from vessel 46leads to a suitable vacuum or suction pump, indicated as venturi pump56, which can: also be connected to the same source of compressed gas assupply line 26, so that suction is applied to vessel- 46and-the samplegas and condensed water are pulled therefrom, whereby the fluid samplestream is pulled through conduit 10 and instrument container 50.

Normally only a small quantity of the incoming fluid sample stream willbe passed through the conduit tube 10 and the analytical instrumentcontainer 50. The great bulk of the fluid sample stream will passdownwardly through lower arm 48 into vessel 46 and then out of thesystem through outlet pipe 54. The lower arm 48 of junction tube 40 andthe discharge line-52 from the. instrument container 50 are positionedrelative to one another in vessel 46 to affect the desired fractioningof the sample gas stream. To increase the flow through discharge line52, for example, it is raised relative to lower arm 48.

In operation, the fluid sample stream enters through base 44 of junctiontube 40 and is split into two parts, one part passing downwardly throughlower arm 48 directly into vessel 46 and the other part passing upwardlythrough upper arm 42 into the inlet 12 of the conduit tube 10. A gasunder pressure, such as compressed air, is passed into vortex tube 28where it separates into two exit streams, a heated stream and a cooledstream. The cooled stream passes through pipe 32 into heat exchangerelationship in cooling section 18 of jacket l6'with the fluid samplestream so that the fluid sample is cooled. if the fluid sample stream isa water vapor containing gas stream, the sample stream desirably iscooled sufficiently to condense the water vapor, which will run down theinside of conduit tube 10 and junction tube 40 into vessel 46. Theheated stream from the vortex tube 28 passes through pipe 30 andregulator valve 38 into the upper or heating section 20 of jacket 16where it .is in heat exchange relationship with the cooled fluid sampleand heats the fluid sample. Thus, the fluid sample, its temperaturehaving been raised, is no longer saturated with water vapor and watervapor is not likely to condense out in instrument container 50,interfering with the analyses of the gas stream. The heated fluid streamthen passes through container 50 where it is analyzed, for example, foroxygen content. The same source of compressed air which is attached tosupply line 26 for the vortex tube may be connected to a vacuum pump 56for drawing a suction on vessel 46. Since discharge line 52 extends intothe vessel 46 from instrument container 50, this also pulls the samplestream through the conduit 10 and instrument container 50 where it isanalyzed. Only a portion of the fluid sample stream is passed into heatexchange relationship with the gas streams from the vortex tube and theremainder passes directly into vessel 46 with the condensed water.

It will be appreciated that the foregoing is only a description of oneprocess and one form of apparatus embodying the principles of theinstant invention. This is for illustrative purposes and the instantinvention is not to be limited thereby but only by the claims whereinwhat is claimed is:

1. Apparatus for conditioning a fluid sample stream which comprises:

a. a fluid conduit having an inlet and an outlet;

b. a hollow heat exchange jacket, having a cooling section and a heatingsection, surrounding the conduit so as to form a heating sectionand acooling section in the conduit;

c. a vortex tube;

d. means for introducing a gas under pressure into the vortex tube sothat the gas separates into two exit streams from the vortex tube, aheated stream and a cooled stream;

e. means for passing the heated gas stream into the heating section ofthe heat exchange jacket;

f. means for passing the cooled gas stream into the cooling section ofthe heat exchange jacket;

g. means for passing the fluid sample stream through the conduit,traveling through the section surrounded by the cooling section of thejacket and through the section surrounded by the heating section,whereby the fluid sample stream is cooled and heated.

2. The apparatus of claim 1 wherein the two sections of the heatexchange jacket are separated from one another.

3. The apparatus of claim 1 including means for controlling thetemperature differential between the heating and cooling sections.

4. The apparatus of claim 3 wherein the control means is positioned soas to regulate the passage of the heated gas stream from the vortex tubeinto the heating section of the heat exchange jacket.

5. The apparatus of claim '1 wherein the conduit is a generallyvertically disposed tube.

6. The apparatus of claim 5 wherein the vcooling section is below theheating section.

7. The apparatus of claim 5 wherein the fluid sample stream is a watervapor containing gas stream and the cooling section is below the heatingsection, water vapor condensing and separating from the sample stream inthe cooling section, and including as an additional element, means forcollecting the condensed water.

8. The apparatus of claim 7 including a container for an analyticalinstrument mounted on the outlet of the conduit so that the conditionedsample stream passes therethrough.

9. The apparatus of claim 8 including the following additional elements:

a. a vertically disposed junction tube connected at its upper arm to theinlet of the conduit, and at its base to a source of sample gas; i

b. a vessel for collecting condensed water sealed to the lower arm ofthe junction, so that some of the sample gas and the condensed waterpass downwardly into the vessel and the remainder of the sample gaspasses upwardly through the conduit, whereby it is conditioned..

10. The apparatus of claim 9 including the following additionalelements:

a. a sample stream discharge line from the instrument containerextending downwardly into and sealed inthe condensed water vessel;

b. means for applying suction to the vessel so that the sample gas andcondensed water are pulled therefrom, whereby the fluid sample stream ispulled through the conduit and instrument container.

11. The apparatus of claim 10 wherein the means for applying suction isa vacuum pump.

12. The apparatus of claim 10 wherein the lower arm of the junction tubeand the discharge line from the instrument container are positionedrelative to one another in the vessel so that the amount of sample gasfrom the source passing through the conduit is controlled.

13. The method of conditioning a fluid sample stream which compnses:

a. passing a gas under pressure into a vortex tube so that the gasseparates into two exit streams from the vortex tube, a heated streamand a cooled stream;

b. passing the cooled stream into heat exchange relationship with thefluid sample stream so that the fluid sample is cooled; I 1

c. passing the heated stream into heat exchange relationship with thefluid sample stream so that the fluid sample is heated, whereby thefluid sample stream is conditioned.

14. The method of claim'l3 wherein the fluid sample stream is flowinggenerally upward.

stream.

.117. The method of claim 16 including the additional step of: a.passing only a portion of the fluid sample stream into heat exchangerelationship with the gas streams from the vortex tube;

b. separating the remainder of the sample stream with the condensedwater.

1. Apparatus for conditioning a fluid sample stream which comprises: a.a fluid conduit having an inlet and an outlet; b. a hollow heat exchangejacket, having a cooling section and a heating section, surrounding theconduit so as to form a heating section and a cooling section in theconduit; c. a vortex tube; d. means for introducing a gas under pressureinto the vortex tube so that the gas separates into two exit streamsfrom the vortex tube, a heated stream and a cooled stream; e. means forpassing the heated gas stream into the heating section of the heatexchange jacket; f. means for passing the cooled gas stream into thecooling section of the heat exchange jacket; g. means for passing thefluid sample stream through the conduit, traveling through the sectionsurrounded by the cooling section of the jacket and through the sectionsurrounded by the heating section, whereby the fluid sample stream iscooled and heated.
 2. The apparatus of claim 1 wherein the two sectionsof the heat exchange jacket are separated from one another.
 3. Theapparatus of claim 1 including means for controlling the temperaturedifferential between the heating and cooling sections.
 4. The apparatusof claim 3 wherein the control means is positioned so as to regulate thepassage of the heated gas stream from the vortex tube into the heatingsection of the heat exchange jacket.
 5. The apparatus of claim 1 whereinthe conduit is a generally vertically disposed tube.
 6. The apparatus ofclaim 5 wherein the cooling section is below the heating section.
 7. Theapparatus of claim 5 wherein the fluid sample stream is a water vaporcontaining gas stream and the cooling section is below the heatingsection, water vapor condensing and separating from the sample stream inthe cooling section, and including as an additional element, means forcollecting the condensed water.
 8. The apparatus of claim 7 including acontainer for an analytical instrument mounted on the outlet of theconduit so that the conditioned sample stream passes therethrough. 9.The apparatus of claim 8 including the following additional elemeNts: a.a vertically disposed junction tube connected at its upper arm to theinlet of the conduit, and at its base to a source of sample gas; b. avessel for collecting condensed water sealed to the lower arm of thejunction, so that some of the sample gas and the condensed water passdownwardly into the vessel and the remainder of the sample gas passesupwardly through the conduit, whereby it is conditioned.
 10. Theapparatus of claim 9 including the following additional elements: a. asample stream discharge line from the instrument container extendingdownwardly into and sealed in the condensed water vessel; b. means forapplying suction to the vessel so that the sample gas and condensedwater are pulled therefrom, whereby the fluid sample stream is pulledthrough the conduit and instrument container.
 11. The apparatus of claim10 wherein the means for applying suction is a vacuum pump.
 12. Theapparatus of claim 10 wherein the lower arm of the junction tube and thedischarge line from the instrument container are positioned relative toone another in the vessel so that the amount of sample gas from thesource passing through the conduit is controlled.
 13. The method ofconditioning a fluid sample stream which comprises: a. passing a gasunder pressure into a vortex tube so that the gas separates into twoexit streams from the vortex tube, a heated stream and a cooled stream;b. passing the cooled stream into heat exchange relationship with thefluid sample stream so that the fluid sample is cooled; c. passing theheated stream into heat exchange relationship with the fluid samplestream so that the fluid sample is heated, whereby the fluid samplestream is conditioned.
 14. The method of claim 13 wherein the fluidsample stream is flowing generally upward.
 15. The method of claim 13including the additional step of regulating the flow of the heated gasstream so that the temperature differential between the heated andcooled gas stream is controlled.
 16. The method of claim 13 wherein thefluid sample stream is a water vapor containing gas stream and thesample stream is cooled sufficiently by heat exchange with the cooledgas stream to condense the water vapor, and including the additionalstep of separating the condensed water from the sample stream.
 17. Themethod of claim 16 including the additional step of: a. passing only aportion of the fluid sample stream into heat exchange relationship withthe gas streams from the vortex tube; b. separating the remainder of thesample stream with the condensed water.